If it ammonia spike you don't want to add salt. You need to take care of the problem and salt will not help with ammonia problem at all. So do not add salt.
I don't cycle any of the tanks so i am not experienced with cycling. But if its ammonia spike then you need to do more water changes. 3 gall even with a filter you need to do minimum 2-50% water changes a week with vacuuming and cleaning the filter media. I don't remember how much water you been changing?
If you transfer Mojo back and forth to the hospital tank , you can keep him in his main tank , just do more water changes and check ammonia. You can take the filter out and just try to do 2-50% water changes and one full water changes a wk. I would think it would take care of the ammonia.
As i remember you don't have ammonia in your tap water right?
Last edited by ANHEL123; 10-08-2013 at 02:58 PM.